Fig. 2From: The significance of biomass allocation to population growth of the invasive species Ambrosia artemisiifolia and Ambrosia trifida with different densitiesEffect of population density on biomass allocation of two ragweed organs at different growth stages (Mean ± SE). a, b A. artemisiifolia.; c, d A. trifida. Different lowercase letters indicate significant differences in relative organ biomass at the same population density across growth stages (P < 0.05), while different uppercase letters indicated significant differences in relative organ biomass across different densities during one growth stage (P < 0.05)Back to article page